Peptide coupling reagent1,1'-Carbonyldiimidazole acts as a coupling reagent and utilized for coupling of amino acids in order to prepare peptide in organic synthesis. It is also used in the preparation of beta-keto sulfones, sulfoxides and beta-enamino acid derivatives. It is used to convert alcohols and amines into carbamates, esters, and ureas. It is involved in the preparation of formylized imidazole by reaction with formic acid. Further, it is used in the synthesis of dipolar polyamides compounds. In addition to this, it is considered as an equivalent of phosgene and used to prepare asymmetric bis alkyl carbonate.